Start Up
38 RT-SVX25G-EN
Supply Duct Static Setpoint = 2.0" w.c.
(RTAM) deadband = 0.2" w.c. (RTAM)
Duct Static Control Range = 1.9" w.c. to 2.1" w.c.
VHR Relay Output
For standalone VAV unit operation, the VHR output should
be wired to drive VAV boxes to maximum position during
all heating modes and unoccupied periods. The VHR
contacts are shown in the de-energized position and will
switch (energize) during the above mentioned operating
modes.
To configure the proper potentiometer setpoints, connect
a multi-meter across the customer connection header (J7)
to the pins listed in
Table 12 below.
F
igure 28. Supply duct static pressure control
Figure 29. VHR relay output
Table 11. Variable air volume mode operation
Sy st em Mo d e Fan “ Au t o ” Fa n “ On ”
Heat
DWU Act ive
DWU Off
DWU
2
Off
4
DWU
2
VAV Heat ing
4
Cool VAV Cooling
1
VAV Cooling
1
Auto
DWU Act ive
DWU Off
DWU or
Cooling
1, 2, 3, 4
VAV Cooling
1
DWU or
Cooling
1, 2, 3, 4
VAV Cooling or
Heat ing
1
Off Off
4
Off
4
Notes:
1 . I f Cooling is select ed t he supply fan will run continuously. I f VAV
Heating is act ivat ed t he supply fan w ill run continuously.
2 . I f Dayt ime War m up is Act ivat ed, the supply fan w ill run
cont inuously.
3 . Auto changeov er bet ween Cooling and Dayt ime
War m up depends upon t he DWU init iat e set point .
4 . The fan will be Off any t im e the syst em selection swit ch
is “Off” .
Table 12. VAV setpoints
Su p p l y A ir Co o l in g
Set p o in t ( J7 - 3 ,4 )
Re sist a n c e ( Oh m s) DC v o lt s De g F
240 0.97 50.37
280 1.09 52.30
320 1.21 54.24
360 1.32 56.09
410 1.45 58.18
450 1.55 59.80
Su p p l y Ai r Pr essu r e
Set p o in t ( J7 - 1 ,2 )
Re sist a n ce ( Oh m s) DC v o lt s “ W C
100 0.45 0.30
350 1.30 0.98
540 1.75 1.49
730 2.11 2.00
> 900 > 2.38 2. 5
Note: To r educe t he risk of coil freezing, it is not recom m ended t o set t he
supply air tem perat ure set point below 50° F.
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